Electrical apparatus for switching on and off a number of circuits in accordance with a prescribed cycle



April 14, 1953 M. ZUCKERMAN 2,635,154

ELECTRICAL. APPARATUS FOR SWITCHING ON AND OFF A NUMBER OF CIRCUITS IN ACCORDANCE WITH A PRESCRIBED CYCLE Filed Aug. 4, 1950 2 SHEETS-SHEET l u FIGIZ.

IN V EN TOR.

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A ril 14, 1953 M. ZUCKERMAN 2,635,154

ELECTRICAL APPARATUS FOR SWITCHING ON AND OFF A NUMBER OF CIRCUITS IN ACCORDANCE WITH A PRESCRIBED CYCLE Filed Aug. 4. 1950 2 SHEETS-SHEET 2 F|G.4. FIGS.

F5557 CIRCUIT I LINE ope/m r/o/vs C/RCU/T 3 C Patented Apr. 14, 1953 ELECTRICAL APPARATUS FOR SWITCHING ON AND OFF A NUMBER OF CIRCUITS IN ACCORDANCE WITH A PRESCRIBED CYCLE Milton Zuckerman, Brooklyn, N. Y.

Application August 4, 1950, Serial No. 177,606

Claims.

This invention relates to an improved apparatus for electrical switching and more especially to electrical apparatus which is used for switching on and oil a number of circuits in accordance with a prescribed cycle.

Due to the Widespread application of electrical devices, it has become desirable to provide suitable means for automatic control. In particular, the control of devices which perform a series of operations has become an important problem. For example, traffic signals must be switched on and off in a prescribed cycle; washing machines must wash for a certain time interval, rinse for another time interval and dry for still another time interval; automatic screw machines must bring a tool to the work, cut the work, remove the tool, move the work to the next cutting tool, etc. Electrical control for all these mechanisms and countless others is generally used because of its extreme flexibility.

The present invention provides an improved means for switching on and off a number of electrical circuits, and also enables the time which any one circuit is kept on or off to be adjusted. By connecting these circuits to the device which is to be controlled, it is possible to perform one operation for a given time interval and then perform succeeding operations one after the other for different time intervals. After an entire cycle has been completed, the invention automatically repeats the cycle.

In order to carry out the purposes of the invention, the armature of a solenoid is caused to undergo a motion which consists of a series of rectilinear translations with a period of time during which the armature is held at rest between each translation. Upon completion of a series of translations, the armature is automatically attracted to the solenoid and the sequence is repeated. Each time the armature moves, switch contacts are opened or closed, and these contacts may be used to control any suitable device. It is thus simple to cause a given pair of contacts to remain either open or closed for several translations of the armature; and consequently, a control circuit may be energized when desired and remain energized for any desired period of time within the complete cycle of operation.

The motion of the armature is obtained by forming a series of teeth or cams on its opposite edges, engaging a tooth for a period of time to hold the armature at rest, and then allowing the armature to translate the distance between teeth at which time the next tooth becomes engaged to hold the armature at rest for another period of time. To engage the teeth the armature passes through a slotted member which moves back and forth perpendicular to the direction of motion of the armature and engages a tooth on one side of the armature in one position and a tooth on the other side in the opposite position. Furthermore, the slot is so formed that when it moves far enough to release a tooth on one side, a tooth on the opposite side will be engaged when the armature is moved in its direction of motion. In order to achieve this action, it is necessary to form the teeth so that between two teeth on one side of the armature there is one tooth on the opposite side of the armature. Movement of the armature is due to the action of gravity in one form of the invention; and due to the action of a spring in another form of the invention.

A bi-metallic strip is fastened to one end of the slotted member and a restoring member to the other end of the slotted member in order to obtain periodic motion of the slotted member. It is well known that when a bi-metallic strip is heated, as, for example, by passing an electric current through a heater for it, the bi-metallic strip bends, and when the current ceases the strip cools and moves back to its original position. Thus, it is clear that if an electric current passes through a heater for the bi-metallic strip it will cause the slotted member to move in a prescribed direction; and if the current is then stopped the bi-metallic strip will cool and the slotted member will be returned to its initial position because of the return of the bi-metallic strip to the original position and the action of the restoring member.

Automatic heating of the bi-metallic strip is provided for by having a switch in the heating circuit which remains closed every other time the armature comes to rest. Since the armature travels the entire distance between two teeth on one side of the armature in a complete cycle of the restoring member and is held at rest by the engagement of teeth on the same side of the armature every other time the armature is held at rest, it is convenient to have each tooth on one side of the armature close the switch in the heating circuit when it comes to rest at a prescribed position. The arrangement just described will give the slotted member a periodic motion which will enable the armature to move in a series of translations.

Owing to the fact that the rate of heating and cooling of the bi-metallic strip may be dif- 'tened to its-curved surface.

ferent, the time which the slotted member takes to move in one direction may be different from the time taken to return to its initial position. In fact, the heating rate of the bi-metallic strip may be easily controlled by varying the current in the heating circuit. Consequently, the time the armature remains at rest may be different when a tooth on one side is engaged by the slotted member from when a tooth on the opposite side is engaged by the slotted member and may be further varied by controlling the size of the various teeth.

In order to repeat the cycle, the armature must be returned to an initial position after it has completed an entire series of translations. To accomplish this, a reset circuit which attracts the armature to the electromagnet is actuated at the end of a series of translationsby a throw lever attached to the armature. Once the armature is returned to its starting position, the electromagnet is no longer energized because the reset switch is opened and the armature begins a new series of translations.

Cain members which actually open and close the control circuits are attached to the'armature and undergo the same motion as it; Risers are formed on thecam members which contact followers that close the switches in the control circuits for'as long as the follower is deflected. It is therefore apparent that any given control switch mayremain close'd'for'any part of the cycle of the armature by forming a riser of sufficient length. Conversely, by only pushing against the The time when any given switch is closed is dete'rmined by the point where the riser which 'moves the follower of a switch is located with the armature; a rack and pinion may be used to rotatea cylindrical drum, which has cams fas- The cams may be mad'e'removable so that the control mechanisms maybe adjusted for a variety of different switching arrangements.

'ther advantages, objects and purposes of the invention will become apparent from the following description and claims or will otherwisebecome obvious.

For a clearer understanding of the invention, specific embodiments of the invention have been illustrated in the accompanying drawing wherein:

Fig. 1 is a front view of a control switch embodying the invention.

Fig. 2 is a front view of a portion of Fig. 1 showing in detail the mechanism used to cause periodic motion of the armature of Fig. 1.

Fig. 3 is a side sectional view on alternate multiple cam member showing how the'invention may be adapted to actuate a bank of control switches.

Fig. 4 is afront view of another embodiment follower for a short time a specific switch may remain open for most of the armature cycle.

hereafter explained.

4 of the invention which uses a spring to return the armature to its initial position.

Fig. 5 is a sectional view along the line 55 of Fig. 4.

Fig. 6 is a view showing how the motion of the armature may be used to rotate a fixed circular drum. 7

Fig. 7 is a view of the drum'rotated by the mechanism shown in Fig. 6 and also illustrates how the drum may be utilized to actuate control switches.

Fig. 8 is a sectional view along the line 3--8 of Fig. '71

Fig. 9 is a diagram of the reset circuit used in the invention.

Fig. 10 is a diagram of the circuit used for heating the lei-metallic strip.

Fig. 11 is schematic of a typical operations circuit which may be obtained through use of the invention.

Fig. 12 is a front view of the slotted member used in the invention.

Referring specifically to Figs. 1 and Ii} designates' the electromagnetic solenoid which attracts armature l l to it when: a voltage is applied acrossterminals W and V of the solenoid; Armature 1 l is formed of a suitable magnetic material such as a metal and passes through solenoid H! with weighted end 12 011 one side of solenoid-I'LL On the other side of solenoid iii, teeth 13 are formed on the edges of armature H. Along one edge of armature i l, teeth It are equidistant, and the teeth along the other edge of armature H are also equidistant; but are locatedin suchmanner that between each two teeth on one edge of armature H, there is one tooth midway between them on the opposite'edge of armature ll.

Slotted member HLwhich is placed perpendicular to the longitudinal axis of armature H, is used to engage teeth [3 and thereby hold armature i l in a fixed position. Engagement of slotted member [4 with teeth I3 is by means of slot i5 which is formed-in slotted member it and is illustrated in Fig. 12. Fastene'd to one end of slotted member H3 is bi-metallic strip it which passes through electrical heater element H which contains terminal elements-A andB as shown in Fig. 2. At the other end of-slotted membe [4 is restoring member 5-8 which'is made of a suitablev resilient material such as a steelspring or the like. Bi-metallic strip H and restoring-member 28 are fastened to insulating blcc Hiwhich is formed of any suitable insulating materialhaving the requisite strength such'as Bakelite or the like. Also attached to insulating bloc i9 are switch members Eli and 2| which are formed of any suitable resilient materialthat is a good conductor of electricity. On'switchminber 2 [ah'utment 22 is formed which acts in conjunction with preselected teeth i3 of armature H as will he p Terminals C and Dext'en'd from switch members 26 and 2 respectively as shown in Fig. 2. I

V The action '01 all the foregoing elements in producing a periodic motion of the armature which consists ofa series of translationsofth'e armature with'a period of time during which the armature is heldat'restbetweeneach uansmean will'now be explained. Teeth 13" Dramaii; and slotted member Hi is moved 'perpendi cular to the longitudinal axis of armature i so as to cause the tooth to become' disengaged,

armature II will begin to fall because of its weighted end I2, but will be stopped by the engagement of the tooth on the opposite side of armature I I with the diametrically opposite edge of slot I5. If the direction of motion of slotted member I4 is reversed, the tooth on the opposite side of armature II will become disengaged and the armature will fall again due to weighted end I2 and be stopped by the engagement of a tooth I3 on the side of armature H which is directly above the tooth I3 that was holding armature I I at the beginning of the cycle. From the foregoing description, it is clear that armature II will undergo a series of translations if slotted member I4 is moved periodically in a direction perpendicular to the longitudinal axis of armature II.

Periodic motion of slotted member I4 is obtained by means of the heater circuit shown schematically in Fig. 10. When switch S2 is closed an electric current will pass through terminals A and B of heater I1 and cause bi-metallic strip is to bend. The bending of bi-metallic strip It moves slotted member I4 perpendicular to the longitudinal axis of armature II which, heretofore, as explained caused armature II to undergo a translation. It now S2 is opened, heater element M will cool and bimetallic strip it together with slotted member I will be moved towards their initial positions because of the action of the bimetallic element and restoring member I8. The return movement of slotted member It also causes another translation of armature I I. It is clear that switch S2 must be closed every other time armature II is at rest in order to give slotted member I4 the required periodic motion. Automatic closing of switch S2 every other time armature II is at rest is provided for by having abutment 22 of switch S2 contact every tooth I3 on one side of armature I I. Since the armature translates the distance between two teeth I3 on one of its sides in a complete cycle of slotted member I4, it is apparent that the next tooth IS on the same side of armature II will come to rest in contact with abutment 22 every other time armature II is held at rest. Reference to Fig. 2 will make the closing cycle of switch S2 clear. At the instant shown in Fig. 2 armature II is held through the engagement by slotted member I4 of a tooth I3 on the side of armature II nearest to bi-metallic strip I8; and switch S2 is closed allowing bi-netallic strip I6 to be heated. After a time, bi-metallic strip It will bend and cause slotted member I4 to move and disengage armature II. Armature I I will now fall due to the gravitational efiect of weighted end It but the engagement of a tooth I3 on the side of armature II nearest to S2 will cause armature I I to be held at rest. Switch S2 is now open because abutment 22 lies between two teeth I3 and therefore bi-metallic strip I6 will cool. Restoring member I8 will, after a time, return slotted member I4 to its original position. As slotted member I4 is returned to its original position, armature II will become disengaged from the tooth I3 holding it and begin to fall. However, armature II will be stopped once again by the engagement of a tooth I3 on the side of armature II nearest oi-metallic strip I6. The situation is now the same as the one illustrated in Fig. 2 except that armature II has descended the distance between teeth I3 on one side of the armature II, and the entire cycle begins to repeat itself.

In addition to the series of translations of armature II whose operation has just been described, armature II must be restored to its original position after a complete series of translations. To accomplish this purpose, the reset circuit shown schematically in Fig. 9 is used. When switch S1 illustrated in Figure 1 is closed by the tilting movement of throw lever 23 which is moved downward simultaneously with cam member 24 to which it is secured, electromagnetic solenoid III will be energized and armature II will be attracted to solenoid I0 so that the lowest tooth I3 will be engaged by slotted mem ber I I. Teeth I3 are formed with inclined rear portions so that when armature II moves upward, slotted member I4 will automatically be moved in the correct direction to prevent the engagement of any of the teeth of armature II. Switch S1 is closed by throw lever 23 which is located so that it closes S1 when armature II is at its lowest point. Throw lever 23 is pivotally secured to cam 24 and relaxes its tension against S1 as it moves downwardly, permitting S1 to close.

The motion of armature II which has just been described is utilized to perform actual switching of control circuits by attaching cam member 24 to it. One cam member 24 is shown in Fig. 1 although more than one may be used by joining them behind each other to form a bank. A typical bank consisting of two members 2 is shown in Fig. 3. Risers 25 are formed on cam member 24, and these risers 25 actuate followers 26 of control circuit switches 21. Contro1 switches 27 are of any suitable type and may be conveniently attached to insulating block I3 as shown in Fig. 1 By forming risers 25 at a specified position along armature II, any given circuit may be closed at a desired point in the cycle of armature II. Likewise, by forming risers 25 of sufficient length a given circuit may be kept closed for as long a portion of the cycle of armature I I as desired. Using two cam members 24 shown in Fig. 3, both members close control switches of circuits 2 and 4 simultaneously whereas circuits I and 3 are only closed by one cam member separately. Thus it is possible to close any number of control switches simultaneously by using a bank of cam members 2 3. While the use of cam members to close control switches has been shown, it is obvious that the cam members may be used to open control switches instead of close them.

A typical series of operations which may be obtained by using two selector cam members 24 is shown in Fig. 11. Circuits I through 3 are controlled by one selector cam; whereas circuits 4 through 6 are controlled by another selector cam.

For many applications of the invention the use of weighted end I2 and gravity is impractical and inconvenient. The modification shown in Figs. 4 and 5 has been developed to overcome these objections. Instead of using gravity, spring 23 causes armature II to move when slotted member i l is moved perpendicularly to the longitudinal axis of armature II. Spring 23 is fastened to shaft 29 and acts against member to which may be a manual set hand and which projects from armature II. Member 30 may be also used to actuate cam selector member 3| and thereby close control switches 21 of Fig. 5. In all other respects the operation of this modification of the invention is identical with the one heretofore described.

A modification of the invention in which the cam selector members are adjustable is illustrated in Figs. 6, 7 and 8. The motion of armature ll is converted to a rotary motion of cylindrical hollow drum 32 through the action of rack and pinion 34. Rack 33 is integral with armature I l and has teeth 35 which mesh with teeth SG-of pinion 33, to convert, as is well known, translations of rack E i to rotations of pinion; 33. Pinion 83 rotates on shaft 37 to which hollow drum 32 is fastened; Any suitable material-which is readily machined and has the necessary structural properties may be used to form all of these parts.

The'surface of hollow drum 32 has a plurality of holes 33 which are adapted to receive cams Cams 39 move followers :39 and thereby actuate the circuits which are to be controlled. As shown in Figs. 7 and 8, holes 38 of cylindrical drum 32 are form'edalong circles on the surface of drum 32; and cams 39 are readily removed from these holes. By moving a earn 3% along any given circle the time when the follower E actuated by that particular cam 33 will be moved in the relation to the period of the motion of armature H may be varied. Furthermore, the use of longer and shorter cams 39 in the holes 323 of a given circle will enable the time during which follower lll is deflected to'be adjusted. The result of this arrangement is to provide a mechwhich may be easily adjusted to meet a large variety of control'situations.

Preferred embodiments of the invention have been shown and described. It is apparent that many changes, additions and modifications may be made without departing from the spirit and scope of the invention, as herein disclosed and hereinafter claimed.

Having disclosed the invention what is claimed as new is:

1. An elcctric'al'switchcomprising an armature, said armature including a plurality of teeth displaced one from the other along the longitudinal opposite edges'thereof, a slotted member including a slot therein and having said armature passing through said slot, the edges of said slot being of a width to cause said slot to'eng'age alternate teeth on opposite sides of said armature, a supporting block, a oi-metallic strip having one extremity thereof secured to said bloat: and the other extremity thereof secured to said slotted member, a restoring member havcne extremity thereof secured to said bloc; and the other extremity thereof secured to said slotted member, a heater proximate said himetallic element, a first switch in electrical'circuit with said bi-metallic element and secured to said block, said teeth on one side of said armature closing said first switch at predetermined positions thereof, an electromagnet, a second switch in series electrical circuit with said 'electromagnet, means secured to said armature for closing said second switch at a predetermined position of said armature, a third switch secured to said block and a cam secured to'said armature, said cam opening and closing said third switch at predetermined positions of said armature.

2. An electrical switch as in claim 1, wherein saiol' third switch comprises a plurality of switch members and said cam member includes a plurality of means for selectively opening and closing said switch members at predetermined positions of said armature.

*3. An electrical switch as in claim 1, wherein said third switch comprises a plurality of switch members, each of said switch members including a finger and said cam member including a plurality'of risers, said risers moving said fingers at predetermined positions of said armature to open andclose-selectively said switch members.

4. An electrical switch comprising an armature, said armature including a plurality of teeth displaced one from the other along the longitudinal opposite edges thereof, a slotted member including a slot therein and having said armature passing through said slot, the edges or" said slot being spaced apart a width to cause said slot to engage alternate teeth on opposite sides of said armature, a supporting block, a bi-metallic strip having one extremity thereof secured to said block and the other extremity thereof secured to said slotted. member, a heater proximate said bi-metallic element, a first switch in electrical circuit with said bi-metallic element and secured to said block, said teeth on one side of said armature closing said first switch at predetermined positions thereof, an electromagnet proximate said armature and adapted to attract said armature as an electric current is passed therethrough, a second switch in series electrical ircuit with said electromagnet, means secured to said armature for closing said second switch at a predetermined position of said armature, a third switch secured to said block, a rack gear secured to said armature, a cylindrical drum including raised areas thereon and a pinion gear secured thereto, said pinion gear in mesh with said rack gear and said raised areas opening and closing said third switch as said armature is at predetermined positions.

5. An electrical switch as in claim 4, wherein said third switch comprises a plurality of switch members and said cylindrical drum includes a plurality of raised areas for opening and closing said switch members as said armature is at predetermined positions.

MILTON ZUCKERMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 585,915 Johnston July 6, 1897 744,173 Dresser Nov. 17, 1993 795,235 Richards et al July 18, 1905 950,336 Marsh Feb. 22, 1910 1,192,318 Callow July 7, 1914 1,253,368 Smith Mar. 5, 1918 1,429,525 Olden Sept. 19, 1922 1,950,115 Kuenzli et a1. Mar. 6, 1934 2,060,299 Gensburg Nov. 10, 1936 2,468,996 Olson 1. May 3, 1949 

